Agricultural cultivators are commonly pulled by a tractor to work the soil of a field. The cultivators may be combined with an applicator that applies agrichemicals, such as fertilizer and/or herbicides/insecticides, in a liquid form to the soil as it is cultivated. The cultivators are often designed to work the soil in rows, and separate applicator nozzles can be used to apply the liquid to the ground for each row. There may be as many as 24 to 48 rows and associated nozzles.
It is not uncommon for these nozzles to become plugged during operation, thereby reducing or completely blocking application of the agrichemicals to the soil. When this occurs, particular rows of the field may receive an inadequate amount of the agrichemicals. This can result in the growth of weeds along those rows in the case of inadequate herbicides and can result in stilted growth in the case of inadequate fertilizers. Often the blockage of the nozzle only becomes apparent to the farmer when such growth abnormalities later appear in the field.
One system provided on agricultural cultivators to assist the operator in estimating the flow to each nozzle is a mechanical system positioned in each agrichemical line. One example of such a system is a series of semi-floatable balls positioned within each of the agrichemical lines, such as the Redball® spray monitor system manufactured by Willmar Fabrication, LLC, of Willmar, Minn.
In the Redball® spray monitor system, liquid supplied to each nozzle is first passed through a clear plastic chamber that contains a red-colored ball. The density of the ball is selected to be denser than the density of the fluid, but light enough that, as fluid flows upward through the chamber, the red ball rises in the chamber. As a result, when fluid is flowing, the ball is elevated within the chamber. If a spray nozzle becomes clogged, the corresponding ball will fall to the bottom of the chamber indicating that the no (or little) fluid is flowing through the associated nozzle.
There are several significant drawbacks with the Redball® spray monitor system: (1) some desired fluids have a dark color, but the Redball® spray monitor system does not work with dark colored fluids because the ball cannot be easily seen through the dark fluid; (2) the Redball® spray monitor system is typically positioned behind the tractor driver, so that the driver must either frequently turn around to look at the monitor, or a camera must be used to feed a cab-mounted display positioned in front of the driver; (3) the Redball® spray monitor system must be mounted in a precise vertical orientation to function properly; and (4) the Redball® spray monitor system is imprecise, in that the system is best suited to simply indicate whether there is liquid flow or not, rather than to quantify the amount of liquid that is flowing.
In addition to spray monitor systems, some farmers utilize a single flow meter for the entire system that indicates the flow rate (i.e., gallons/minute) through the entire system. In other words, the flow meter is arranged between the liquid storage tank and the spray monitors and indicates how much liquid is coming out of the tank. This flow meter does not identify the amount of liquid that is being supplied to each individual nozzle and will not indicate whether liquid is flowing through all nozzles.